Final answer:
The British had the well-trained army and the strongest navy in the world during the period of the Napoleonic Wars and the War of 1812, with a vast fleet that included powerful ships of the line.
Step-by-step explanation:
The side that had a well-trained army and the strongest navy in the world during the period referenced in your question was the British. At the time, the British Navy was considered the most formidable maritime power globally, with a vast number of ships and superior naval technologies. During the Napoleonic Wars and the War of 1812, the British were able to commit about eighty-five ships to fight against the Americans, despite having the bulk of their navy engaged with Napoleon's forces. In contrast, the U.S. Navy was considerably underdeveloped, with less than twenty ships in total, including three forty-four-gun frigates.
The British Navy's superior numbers allowed them to establish a blockade of American ports, and their fleet included powerful ships of the line with multiple gun decks and heavy firepower. Although the U.S. frigates were designed with an emphasis on strength of hull and speed, which allowed some American victories that boosted morale, they could not match the British Navy's overall strength.